public class Test {
    public static void main(String[]args){
        int i = 1;
        int j = 1;
        int ret = 1;
        int sum = 0;
        while(i<=5){
            while(ret<=i){
                j*=ret;
                ret++;
            }
            sum+=ret;
            sum++;
        }
        System.out.println("sum = " +sum);
    }
    public static void main6(String[]args){
        int i = 0;
        int sum = 0;
        while(i<=100){
            sum = sum+=i;
            i++;
        }
        System.out.println(sum);
    }
    public static void main5(String[]args){
        int day = 2;
        switch(day){
            case 1:
                System.out.println("星期一");
                break;
            case 2:
                System.out.println("星期二");
                break;
            case 3:
                System.out.println("星期三");
                break;
            case 4:
                System.out.println("星期四");
                break;
            case 5:
                System.out.println("星期五");
                break;
            case 6:
                System.out.println("星期六");
                break;
            case 7:
                System.out.println("星期天");
                break;
        }
    }

    public static void main4(String[]args){
        int year = 2023;
        if(year%100!=0){
            if(year%4==0){
                System.out.println("是普通闰年");
            }else{
                System.out.println("不是普通闰年");
            }
        }else{
            if(year%400==0){
                System.out.println("是世纪闰年");
            }else{
                System.out.println("不是世纪闰年");
            }
        }
    }
    public static void main3(String[]args){
        int a = -5;
        if(a>0){
            System.out.println("是正数");
        }else if(a==0){
            System.out.println("既不是整数也不要是负数");
        }else{
            System.out.println("是负数");
        }
    }



    public static void main2(String[]args){
        int a = 9;
        if(a%2==0){
            System.out.println("是偶数");
        }else{
            System.out.println("是奇数");
        }
    }

    public static void main1(String[]args){
        int i = 1;
        while(i<=100){
            if(i%5==0&&i%6==0){
                System.out.println(i);
            }
            i++;
        }
    }

}
